Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 20: Organic Semiconductors: Transistors and OLEDs

HL 20.4: Vortrag

Dienstag, 23. März 2010, 10:15–10:30, H15

Electron Mobility in Methanofullerens — •Maria S Hammer¹, Carsten Deibel¹, and Vladimir Dyakonov^1,2 — ¹Experimental Physics VI, Julius-Maximilians-University of Würzburg, Am Hubland, D-97074 W\"urzburg — ²ZAE Bayern, Div. Functional Materials for Energy Technology, Am Hubland, D-97074 Würzburg

Methanofullerenes are the state of the art acceptor-type semiconductors applied in flexible and printed electronic devices, e.g. they are used together with a donor-type polymer in (i) solar cells or (ii) complementary circuits. While the hole transport in polymers has been intensely investigated within the last years, less attention has been drawn to the fundamentals of the transport within methanofullerenes. In the present study, the electron mobility, which strongly depends on the electron density, is investigated.

We utilize the organic field effect transistor (OFET) as it provides a way of probing the mobility within a wide range of electron densities via gate voltage. Nevertheless, the performance of an OFET sensitively depends on electron injection from the contacts and trapping at the dielectric interface. Therefore, in order to assess the transport parameters of methanofullerenes, it is indispensable to vary the work function of the electrodes as well as the insulator. We will investigate and discuss the ambipolar charge transport in dependence of the charge carrier density in [6,6]-phenyl-C61-butyric acid methyl ester and other derivatives, employing a variation of dielectric surfaces and injecting metals.